1. Field of the Invention
The present invention relates generally to a helmet, and more particularly to a helmet-used device capable to automatically adjusting positions of displayed information and a helmet thereof. The device is able to automatically correct a projected image to avoid keystone distortion of the image and is able to automatically adjust the output positions of the graphic and text information of the projected image.
2. Description of the Related Art
U.S. Pat. No. 5,646,784 discloses a conventional helmet display system. The helmet display system has a visor disposed on the helmet. A holographic combiner is formed on the visor. Two image projectors are disposed in the helmet for projecting images onto the holographic combiner on the visor. The holographic combiner serves to reflect the projected images to the eyes of a wearer. Also, the eyes of the wearer can see outer side through the visor.
There is a trend to add information display function to the helmet. However, it is disclosed in any of the conventional techniques how to prevent the image projected to the visor from distorting or deforming when the helmet is under affection of external environment (such as wind blow or shaking).